Kopech, ranked the No. 10 prospect in baseball by MLB.com, had an 11.57 ERA with seven walks and seven strikeouts in seven innings over four spring training games this year. He gave up 12 runs — nine earned — in his last two Cactus League appearances. That included a grand slam to Matt Joyce in the Sox’s 14-0 loss to the Athletics on Sunday.

Even before the struggles over the last two games, it was expected that Kopech would start the year in the minor leagues for more seasoning. He spent most of the 2017 season at Double-A Birmingham and made just three starts at Triple-A Charlotte at the end of the year. The move also makes sense from a service-time perspective.

Kopech is expected to start the season at Charlotte. Sox general manager Rick Hahn explained such reasoning earlier this month.

“You’re talking about a very young pitcher (who) has 15 innings above Double A,” Hahn said. “There are still elements of his development that need to occur at the minor-league level and although he has done a very good job in spring training and we do try to keep an open mind, you also come up with these plays for how a player develops based on their body of work — not four weeks of practice games.

“The good ones have a way of forcing your hand and altering things for you and I do think at some point Michael will likely do that.”

May hit .259 with a triple, an RBI, three walks, 10 strikeouts and six stolen bases over 20 spring games this year.

With the moves, the Sox have 36 players in major-league camp – 20 pitchers, three catchers, seven infielders and six outfielders.